Make sure getAttribute() / setAttribute() callers use AtomicStrings

Source/core/html/HTMLSourceElement.h

 /*
  * Copyright (C) 2007, 2008, 2010 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 17 matching lines @@
 
 #include "core/html/HTMLElement.h"
 #include "platform/Timer.h"
 
 namespace WebCore {
 
 class HTMLSourceElement FINAL : public HTMLElement {
 public:
     static PassRefPtr<HTMLSourceElement> create(Document&);
 
-    String media() const;
-    String type() const;
+    const AtomicString& media() const;
+    const AtomicString& type() const;
     void setSrc(const String&);
-    void setMedia(const String&);
-    void setType(const String&);
+    void setMedia(const AtomicString&);
+    void setType(const AtomicString&);
 
     void scheduleErrorEvent();
     void cancelPendingErrorEvent();
 
 private:
     explicit HTMLSourceElement(Document&);
 
     virtual InsertionNotificationRequest insertedInto(ContainerNode*) OVERRIDE;
     virtual void removedFrom(ContainerNode*) OVERRIDE;
     virtual bool isURLAttribute(const Attribute&) const OVERRIDE;
 
     void errorEventTimerFired(Timer<HTMLSourceElement>*);
 
     Timer<HTMLSourceElement> m_errorEventTimer;
 };
 
 DEFINE_NODE_TYPE_CASTS(HTMLSourceElement, hasTagName(HTMLNames::sourceTag));
 
 } // namespace WebCore
 
 #endif